I've been running the following tire size on my vette for years:
225-70-R15. I now believe that the tires may be causing my fender to
crack along the seams. If I turn the wheel, and hit a bump, the under
side of the fender sometimes touches the tire.

I've run 235/60R-15 on a '68 with 8 inch Rally wheels with no rub. The '68
and '69 have slightly smaller fenders than the '70 to '72.

If you are running the 7 inch Rallies, you are missing out on what your car
can do. Only use the 7s for show on a '68. The '69 should have the 8 inch.

I found 255/60R-15 to rub the emergency brake cable bracket on a '68 with
the Rally wheels. The Aluminum '76-up Corvette wheels have about 3/8 - 1/2
inch more offset and so a 255/60R-15 will fit the rear with the Aluminum
wheels. I can't remember if they rubbed anywhere on front.

In '78, they put the 255/60R-15 on as the optional tire. They did trim the
underside of the fender lip at the factory.

Many are putting 50 series and 40 series on 16 inch rims and getting even
wider. Something to think about.

You can put a lot more tire under with the lower profile series and get much
better handling.

Your original size was F70-15, which if memory serves is a 215/70 - 15.

If you are running aftermarket wheels, then you need to be sure that your
backspacing is the same as the rally wheels (3-1/2 inches) and the wheel is
8 inches wide.

Do not go skinnier because you will not like the way it handles. Let's say
it is embarrassing that nearly any Chevy truck will go faster through the
curves than your Corvette on skinny tires.

Tom had good info ; im running a set of 255x60r15's on my 1970 without
any problems with clearance. I used to have 235x70r15's ..... the 255's
put more meat to the road and handling is greatly improved.

My primary problem here is cracks in the fender when I turn the wheel. So,
let me ask you: Even though the clearance on my '69 might be different from
the clearance on your '70, did the 235-70-15's contribute to any cracks
along the seam of either of your fenders?

I my last note, I meant to say that I have a problem when I turn the wheel,
and HIT A BUMP. the fender sometimes comes in contact with the turned tire,
and may be contributing to cracks that eventually appear in the seam of my
fender.

Have you seen this problem with any of the tires you've used on your '70
vette?

Charles... If you are talking about the horizontal seams toward the top of
all four fenders, these began to show after only a few years on many of
these cars. It is the result of the fiberglass and/or bonding material
shrinking which causes cracks in the paint along the seam. I don't think
minor tire contact with the fender would accelerate this "aging" process.

My 72 shows the seams all up and down both sides. I am running 235/70-15s
which contact the fender lip slightly on turns ( I plan to change to 225s).
As others have said, you can go with 255/60s or 215/70s to stop the contact.

Good luck - Joe, 72 coupe

joe m

8
17th May 02:07

charles halliman

External User

Posts: 1

'69 Vette Correct Tire Size

Joe,

I'm considering 225-60-R15. This would retain the width I now have, but lower
the height of the tire. I'm hoping this will greatly minimize the fender
contact. In your opinion, am I right about this?

Charles, Cracks on the top seams of corvette fenders is part of the
trademark with all C3's . I doubt it was because of the 235x70R15's i
had on there....i think they are a combo of stress and most likely poor
preparation of surface by whoever painted my corvette last.

The 225/60 is about 2 inches in diameter smaller than the 225/70. This
should run with no fender contact, but will also put the car 1 inch closer
to the ground increasing the odds of chassis parts contacting the road!.. If
fender contact is only slight when turning, I would try the 215/70-15 (this
is the modern equivalent of the original F70-15)...
This should give fender clearance without losing too much ground clearance.
You don't need more tire width unless you are into hard cornering. Use the
225/60 in that case. - Joe